For many years manufacturers have supplied users of electrical connector components with electrical contacts for terminating an insulated conductor wire. One termination method commonly used has been to mechanically strip the insulation from the wire to expose a conductive end portion of the wire and then to crimp a portion of the contact sleeve to the wire end by controlled compression and displacement of the contact metal. Some of the steps necessary to obtain a desired crimp depend on or are a function of wire end preparation, crimp depth and control of the crimp depth. The crimp depth must be predetermined for each contact-to-wire application and is obtained by a crimping tool indentor. Controlling the crimp depth is established by ratchet means on the crimping tool which allow the crimping tool's handles to reach full closure (representing the bottoming position of the crimping operation) and the indentor to be released. Irrespective of contact sleeve size, the crimping mechanism release point and indentor bottoming position must be selected by the operator.
One major disadvantage with the above approach is that the wire must be prepared first. A wire stripping operation is not only time consuming but care must be taken in selecting the tool which strips the insulation so as to avoid damage to the conductors. A further disadvantage with the above method is that the tool operator could mistakenly select improper crimping settings, thereby resulting in poor and/or unacceptable terminated wire-to-contact interconnections.
Another method of electrically terminating an insulated wire is by an insulation displacement technique. The insulation displacement method of terminating a wire to an electrical contact requires no previous removal of the insulation from a wire before assembly. In this form of electrical termination the wire typically lays across a pair of spaced slots. An assembly tool typically wedges each wire home into a slot of the contact receiving the wire and a contact portion pierces and/or displaces the insulation surrounding the conductive wire portion. Typical examples of insulation piercing contacts are illustrated by U.S. Pat. Nos. 3,012,219; 3,147,058; 3,617,983; 3,879,099 and 3,964,816.
A major disadvantage with the above technique, is the need for a plastic (molding) housing to retain the insulated conductors in the terminated position. Without this protection, the terminated connection will not be locked in place and the interconnection would not be strain relieved. A further disadvantage with this method is that the assembly tool must bear down onto the housing to force the wire inwardly of a wire receiving slot of the contact. The reliability of the termination in the slot is not certain. In some multi-termination apparatus shown by the prior art, to replace one contact-to-conductor termination, all of the terminations need to be dislodged and then reestablished.
A more desirable contact would be one which provides the user with a contact that is self-contained, which provides means for assuring that the wire is properly positioned for termination, which may be used without requiring a separate housing molding, which provides a sturdy insulation piercing member, which encloses the wire and strain relieves the termination and which locks the contact and the wire termination achieved.